There are applications, especially in penal institutions, in which a door closure will have a sensing element, or door position activated switch, which can track the door condition: open or closed, and report the condition to a remote monitoring station for security reasons. At the remote monitoring station, the reported condition is signalled either audibly or optically. Such a sensing or door position activated switch is disclosed in U.S. Pat. No. 4,835,905.
Known products which have this feature can be compromised. The wires and connectors used to report the door condition can be connected improperly, by inadvertence or design, to report a door closed condition to the remote monitoring station when, in fact, the door is not closed, is not secured. To overcome this problem, it is conceivable to use two, separate switches. One would report to the remote station, and the other would report to wires at the door. However, in practice, it is extremely difficult or impossible to have the two switches aligned accurately enough to be used.
What has been long needed is a single controlling switch, used in combination with the sensing or door position activated switch, which can be operated to report the door condition to the remote station, while isolating a local signal assembly at the door, and can be operated to report the door condition, accurately, to such a local signal assembly, at the door. Ideally, operation of such a controlling switch would maintain a door-open signal, at the remote station, all the while that the local signal assembly is being operated to set or establish the correct functioning of the door sensing element in the door closure.